Evolution of Magnetic Hyperthermia for Glioblastoma Multiforme Therapy

Magnetic Hyperthermia in Glioblastoma Multiforme Treatment

Glioblastoma multiforme (GBM) represents one of the most critical oncological diseases in neurological practice, being considered highly aggressive with a dismal prognosis. At a worldwide level, new therapeutic methods are continuously being researched. Magnetic hyperthermia (MHT) has been investigated for more than 30 years as a solution used as a single therapy or combined with others for glioma tumor assessment in preclinical and clinical studies. It is based on magnetic nanoparticles (MNPs) that are injected into the tumor, and, under the effect of an external alternating magnetic field, they produce heat with temperatures higher than 42 °C, which determines cancer cell death. It is well known that iron oxide nanoparticles have received FDA approval for anemia treatment and to be used as contrast substances in the medical imagining domain. Today, energetic, efficient MNPs are developed that are especially dedicated to MHT treatments. In this review, the subject's importance will be emphasized by specifying the number of patients with cancer worldwide, presenting the main features of GBM, and detailing the physical theory accompanying the MHT treatment. Then, synthesis routes for thermally efficient MNP manufacturing, strategies adopted in practice for increasing MHT heat performance, and significant in vitro and in vivo studies are presented. This review paper also includes combined cancer therapies, the main reasons for using these approaches with MHT, and important clinical studies on human subjects found in the literature. This review ends by describing the most critical challenges associated with MHT and future perspectives. It is concluded that MHT can be successfully and regularly applied as a treatment for GBM if specific improvements are made.

What is the Reason That the Pharmacological Future of Chemotherapeutics in the Treatment of Lung Cancer Could Be Most Closely Related to Nanostructures? Platinum Drugs in Therapy of Non-Small and Small Cell Lung Cancer and Their Unexpected, Possible Interactions. The Review

Over the course of several decades, anticancer treatment with chemotherapy drugs for lung cancer has not changed significantly. Unfortunately, this treatment prolongs the patient's life only by a few months, causing many side effects in the human body. It has also been proven that drugs such as Cisplatin, Carboplatin, Oxaliplatin and others can react with other substances containing an aromatic ring in which the nitrogen atom has a free electron group in its structure. Thus, such structures may have a competitive effect on the nucleobases of DNA. Therefore, scientists are looking not only for new drugs, but also for new alternative ways of delivering the drug to the cancer site. Nanotechnology seems to be a great hope in this matter. Creating a new nanomedicine would reduce the dose of the drug to an absolute minimum, and thus limit the toxic effect of the drug; it would allow for the exclusion of interactions with competitive compounds with a structure similar to nucleobases; it would also permit using the so-called targeted treatment and bypassing healthy cells; it would allow for the introduction of other treatment options, such as radiotherapy directly to the cancer site; and it would provide diagnostic possibilities. This article is a review that aims to systematize the knowledge regarding the anticancer treatment of lung cancer, but not only. It shows the clear possibility of interactions of chemotherapeutics with compounds competitive to the nitrogenous bases of DNA. It also shows the possibilities of using nanostructures as potential Platinum drug carriers, and proves that nanomedicine can easily become a new medicinal product in personalized medicine.

Design of the distribution of iron oxide (Fe3O4) nano-particle drug in realistic cholangiocarcinoma model and the simulation of temperature increase during magnetic induction hyperthermia

The prognosis for Cholangiocarcinoma (CCA) is unfavorable, necessitating the development of new therapeutic approach such as magnetic hyperthermia therapy (MHT) which is induced by magnetic nano-particle (MNPs) drug to bridge the treatment gap. Given the deep location of CCA within the abdominal cavity and proximity to vital organs, accurately predict the individualized treatment effects and safety brought by the distribution of MNPs in tumor will be crucial for the advancement of MHT in CCA. The Mimics software was used in this study to conduct three-dimensional reconstruction of abdominal computed tomography (CT) and magnetic reso-nance imaging images from clinical patients, resulting in the generation of a realistic digital geometric model representing the human biliary tract and its adjacent structures. Subsequently, The COMSOL Multiphysics software was utilized for modeling CCA and calculating the heat transfer law resulting from the multi-regional distribution of MNPs in CCA. The temperature within the central region of irregular CCA measured approximately 46°C, and most areas within the tumor displayed temperatures surpassing 41°C. The temperature of the inner edge of CCA is only 39 ∼ 41℃, however, it can be ameliorated by adjusting the local drug concentration through simulation system. For CCA with diverse morphologies and anatomical locations, the multi-regional distribution patterns of intratumoral MNPs and a slight overlap of drug distribution areas synergistically enhance intratumoral temperature while ensuring treatment safety. The present study highlights the practicality and imperative of incorporating personalized intratumoral MNPs distribution strategy into clinical practice for MHT, which can be achieved through the development of an integrated simulation system which incorporates medical image data and numerical calculations.

In Vitro Superparamagnetic Hyperthermia Employing Magnetite Gamma-Cyclodextrin Nanobioconjugates for Human Squamous Skin Carcinoma Therapy

In vitro alternative therapy of human epidermoid squamous carcinoma (A431) by superparamagnetic hyperthermia (SPMHT) using Fe3O4 (magnetite) superparamagnetic nanoparticles (SPIONs) with an average diameter of 15.8 nm, bioconjugated with hydroxypropyl gamma-cyclodextrins (HP-γ-CDs) by means of polyacrylic acid (PAA) biopolymer, is presented in this paper. The therapy was carried out at a temperature of 43 °C for 30 min using the concentrations of Fe3O4 ferrimagnetic nanoparticles from nanobioconjugates of 1, 5, and 10 mg/mL nanoparticles in cell suspension, which were previously found by us to be non-toxic for healthy cells (cell viabilities close to 100%), according to ISO standards (cell viability must be greater than 70%). The temperature for the in vitro therapy was obtained by the safe application (without exceeding the biological limit and cellular damage) of an alternating magnetic field with a frequency of 312.4 kHz and amplitudes of 168, 208, and 370 G, depending on the concentration of the magnetic nanoparticles. The optimal concentration of magnetic nanoparticles in suspension was found experimentally. The results obtained after the treatment show its high effectiveness in destroying the A431 tumor cells, up to 83%, with the possibility of increasing even more, which demonstrates the viability of the SPMHT method with Fe3O4-PAA-(HP-γ-CDs) nanobioconjugates for human squamous cancer therapy.

Magnetic nanoparticles in square-wave fields for breakthrough performance in hyperthermia and magnetic particle imaging

Driving immobilized, single-domain magnetic nanoparticles at high frequency by square wave fields instead of sinusoidal waveforms leads to qualitative and quantitative improvements in their performance both as point-like heat sources for magnetic hyperthermia and as sensing elements in frequency-resolved techniques such as magnetic particle imaging and magnetic particle spectroscopy. The time evolution and the frequency spectrum of the cyclic magnetization of magnetite nanoparticles with random easy axes are obtained by means of a rate-equation method able to describe time-dependent effects for the particle sizes and frequencies of interest in most applications to biomedicine. In the presence of a high-frequency square-wave field, the rate equations are shown to admit an analytical solution and the periodic magnetization can be therefore described with accuracy, allowing one to single out effects which take place on different timescales. Magnetic hysteresis effects arising from the specific features of the square-wave driving field results in a breakthrough improvement of both the magnetic power released as heat to an environment in magnetic hyperthermia treatments and the magnitude of the third harmonic of the frequency spectrum of the magnetization, which plays a central role in magnetic particle imaging.

Self-propelling bacteria-based magnetic nanoparticles (BacMags) for targeted magnetic hyperthermia therapy against hypoxic tumors

Magnetic hyperthermia-based cancer therapy (MHCT) holds great promise as a non-invasive approach utilizing heat generated by an alternating magnetic field for effective cancer treatment. For an efficacious therapeutic response, it is crucial to deliver therapeutic agents selectively at the depth of tumors. In this study, we present a new strategy using the naturally occurring tumor-colonizing bacteria Escherichia coli (E. coli) as a carrier to deliver magnetic nanoparticles to hypoxic tumor cores for effective MHCT. Self-propelling delivery agents, "nano-bacteriomagnets" (BacMags), were developed by incorporating anisotropic magnetic nanocubes into E. coli which demonstrated significantly improved hyperthermic performance, leading to an impressive 85% cell death in pancreatic cancer. The in vivo anti-cancer response was validated in a syngeneic xenograft model with a 50% tumor inhibition rate within 20 days and a complete tumor regression within 30 days. This proof-of-concept study demonstrates the potential of utilizing anaerobic bacteria for the delivery of magnetic nanocarriers as a smart therapeutic approach for enhanced MHCT.

Visualization Materials Using Silicon-Based Optical Nanodisks (ViSiON) for Enhanced NIR Imaging in Ophthalmology

ViSiON (visualization materials composed of silicon-based optical nanodisks) is presented, which offers a unique optical combination of near-infrared (NIR) optical properties and biodegradability. Initially, numerical simulations are conducted to calculate the total extinction and scattering effects of ViSiON by the diameter-to-thickness ratio, predicting precise control over its scattering properties in the NIR region. A top-down patterning technique is employed to synthesize ViSiON with accurate diameter and thickness control. ViSiON with a 50 nm thickness exhibits scattering properties over 400 times higher than that of 30 nm, rendering it suitable as a contrast agent for optical coherence tomography (OCT), especially in ophthalmic applications. Furthermore, ViSiON possesses inherent biodegradability in media, with ≈95% degradation occurring after 48 h, and the degradation rate can be finely tuned based on the quantity of protein coating applied to the surface. Subsequently, the OCT imaging capability is validated even within vessels smaller than 300 µm, simulating retinal vasculature using a retinal phantom. Then, using an ex ovo chick embryo model, it is demonstrated that ViSiON enhances the strength of protein membranes by 6.17 times, thereby presenting the potential for ViSiON as an OCT imaging probe capable of diagnosing retinal diseases.

Fe3O4@Chitosan@ZIF-8@RVG29, an anti-glioma nanoplatform guided by fixed and activated by alternating magnetic field

There is considerable interest in developing anti-glioma nanoplatforms. They make the all-in-one combination of therapies possible. Here we show how the selective Glioblastoma multiforme (GBM) cell killing of the here-established nanoplatforms increased after each coating and how the here-established vibration-inducing Alternating magnetic field (AMF) decreased the treatment time from 72 h to 30 s. Thanks to their magnetite core, these nanoplatforms can be guided to the tumor's specific site by a Fixed magnetic field, they bypass the Blood-Brain Barrier (BBB) and accumulate at the tumor site thanks to the RVG29 bonding to the G-protein on the ion-gated channel receptor known as the nicotinic acetylcholine receptor (nAchR), which expresses on BBB cells and overexpresses on GBM cells, and thanks to the positive charge gained by both chitosan and RVG29's peptide. Both ZIF-8 and its mediate adherence, Chitosan increases the drug loading capacity that stimuli response to the tumor's acidic environment. The Zn2+ ions generated from ZIF-8 sustained degradation in such an environment kill the GBM cells. Dynamic Light Scattering (DLS) evaluated these nanoplatform's mean size 155 nm indicating their almost optimum size for brain applications. Based on their elements' intrinsic properties, these nanoplatforms can enhance and combine other adjuvant therapies.

The Curie temperature: a key playmaker in self-regulated temperature hyperthermia

The Curie temperature is an important thermo-characteristic of magnetic materials, which causes a phase transition from ferromagnetic to paramagnetic by changing the spontaneous re-arrangement of their spins (intrinsic magnetic mechanism) due to an increase in temperature. The self-control-temperature (SCT) leads to the conversion of ferro/ferrimagnetic materials to paramagnetic materials, which can extend the temperature-based applications of these materials from industrial nanotechnology to the biomedical field. In this case, magnetic induction hyperthermia (MIH) with self-control-temperature has been proposed as a physical thermo-therapeutic method for killing cancer tumors in a biologically safe environment. Specifically, the thermal source of MIH is magnetic nanoparticles (MNPs), and thus their biocompatibility and Curie temperature are two important properties, where the former is required for their clinical application, while the latter acts as a switch to automatically control the temperature of MIH. In this review, we focus on the Curie temperature of magnetic materials and provide a complete overview beginning with basic magnetism and its inevitable relation with Curie's law, theoretical prediction and experimental measurement of the Curie temperature. Furthermore, we discuss the significance, evolution from different types of alloys to ferrites and impact of the shape, size, and concentration of particles on the Curie temperature considering the proposed SCT-based MIH together with their biocompatibility. Also, we highlight the thermal efficiency of MNPs in destroying tumor cells and the significance of a low Curie temperature. Finally, the challenges, concluding remarks, and future perspectives in promoting self-control-temperature based MIH to clinical application are discussed.

A Novel Port to Facilitate Magnetic Hyperthermia Therapy for Glioma

High-grade gliomas (HGG) are the most common primary brain malignancy and continue to be associated with a dismal prognosis (median survival rate of 15-18 months) with standard of care therapy. Magnetic hyperthermia therapy (MHT) is an emerging intervention that leverages the ferromagnetic properties of magnetic iron-oxide nanoparticles (MIONPs) to target cancer cells that are otherwise left behind after resection. We report a novel port device to facilitate localization, delivery, and temperature measurement of MIONPs within a target lesion for MHT therapy. We conducted an in-depth literature and intellectual property review to define specifications of the conceived port device. After setting the design parameters, a thorough collaboration with neurological surgeons guided the iterative modeling process. A prototype was developed using Fusion 360 (Autodesk, San Rafael, CA) and printed on a Form 3 printer (Formlabs, Medford, MA) in Durable resin. The prototype was then tested in a phantom skull printed on a Pro-Jet 660Pro 3D printer (3D Systems, Rock Hill, SC) and a brain model based on mechanical and electrochemical properties of native brain tissue. This phantom underwent MHT heating tests using an alternating magnetic field (AMF) sequence based on current MHT workflow. Successful localization, delivery, and temperature measurement were demonstrated. The purpose of this study was twofold: first, to create and validate the procedural framework for a novel device, providing the groundwork for an upcoming comprehensive animal trial and second, to elucidate a cooperative approach between engineers and clinicians that propels advancements in medical innovation.

Helios as a Potential Biomarker in Systemic Lupus Erythematosus and New Therapies Based on Immunosuppressive Cells

The Helios protein (encoded by the IKZF2 gene) is a member of the Ikaros transcription family and it has recently been proposed as a promising biomarker for systemic lupus erythematosus (SLE) disease progression in both mouse models and patients. Helios is beginning to be studied extensively for its influence on the T regulatory (Treg) compartment, both CD4+ Tregs and KIR+/Ly49+ CD8+ Tregs, with alterations to the number and function of these cells correlated to the autoimmune phenomenon. This review analyzes the most recent research on Helios expression in relation to the main immune cell populations and its role in SLE immune homeostasis, specifically focusing on the interaction between T cells and tolerogenic dendritic cells (tolDCs). This information could be potentially useful in the design of new therapies, with a particular focus on transfer therapies using immunosuppressive cells. Finally, we will discuss the possibility of using nanotechnology for magnetic targeting to overcome some of the obstacles related to these therapeutic approaches.

Flavonoids Regulate Redox-Responsive Transcription Factors in Glioblastoma and Microglia

The tumor microenvironment (TME) has emerged as a valuable therapeutic target in glioblastoma (GBM), as it promotes tumorigenesis via an increased production of reactive oxygen species (ROS). Immune cells such as microglia accumulate near the tumor and its hypoxic core, fostering tumor proliferation and angiogenesis. In this study, we explored the therapeutic potential of natural polyphenols with antioxidant and anti-inflammatory properties. Notably, flavonoids, including fisetin and quercetin, can protect non-cancerous cells while eliminating transformed cells (2D cultures and 3D tumoroids). We tested the hypothesis that fisetin and quercetin are modulators of redox-responsive transcription factors, for which subcellular location plays a critical role. To investigate the sites of interaction between natural compounds and stress-responsive transcription factors, we combined molecular docking with experimental methods employing proximity ligation assays. Our findings reveal that fisetin decreased cytosolic acetylated high mobility group box 1 (acHMGB1) and increased transcription factor EB (TFEB) abundance in microglia but not in GBM. Moreover, our results suggest that the most powerful modulator of the Nrf2-KEAP1 complex is fisetin. This finding is in line with molecular modeling and calculated binding properties between fisetin and Nrf2-KEAP1, which indicated more sites of interactions and stronger binding affinities than quercetin.

Recent advances in zinc ferrite (ZnFe2O4) based nanostructures for magnetic hyperthermia applications

Spinel ferrite-based magnetic nanomaterials have been investigated for numerous biomedical applications, including targeted drug delivery, magnetic hyperthermia therapy (MHT), magnetic resonance imaging (MRI), and biosensors, among others. Recent studies have found that zinc ferrite-based nanomaterials are favorable candidates for cancer theranostics, particularly for magnetic hyperthermia applications. Zinc ferrite exhibits excellent biocompatibility, minimal toxicity, and more importantly, exciting magnetic properties. In addition, these materials demonstrate a Curie temperature much lower than other transition metal ferrites. By regulating synthesis protocols and/or introducing suitable dopants, the Curie temperature of zinc ferrite-based nanosystems can be tailored to the MHT therapeutic window, i.e., 43-46 °C, a range which is highly beneficial for clinical hyperthermia applications. Furthermore, zinc ferrite-based nanostructures have been extensively used in successful pre-clinical trials on mice models focusing on the synergistic killing of cancer cells involving magnetic hyperthermia and chemotherapy. This review provides a systematic and comprehensive understanding of the recent developments of zinc ferrite-based nanomaterials, including doped particles, shape-modified structures, and composites for magnetic hyperthermia applications. In addition, future research prospects involving pure ZnFe2O4 and its derivative nanostructures have also been proposed.

Highlighted Advances in Therapies for Difficult-To-Treat Brain Tumours Such as Glioblastoma

Glioblastoma multiforme (GBM) remains a challenging disease, as it is the most common and deadly brain tumour in adults and has no curative solution and an overall short survival time. This incurability and short survival time means that, despite its rarity (average incidence of 3.2 per 100,000 persons), there has been an increased effort to try to treat this disease. Standard of care in newly diagnosed glioblastoma is maximal tumour resection followed by initial concomitant radiotherapy and temozolomide (TMZ) and then further chemotherapy with TMZ. Imaging techniques are key not only to diagnose the extent of the affected tissue but also for surgery planning and even for intraoperative use. Eligible patients may combine TMZ with tumour treating fields (TTF) therapy, which delivers low-intensity and intermediate-frequency electric fields to arrest tumour growth. Nonetheless, the blood–brain barrier (BBB) and systemic side effects are obstacles to successful chemotherapy in GBM; thus, more targeted, custom therapies such as immunotherapy and nanotechnological drug delivery systems have been undergoing research with varying degrees of success. This review proposes an overview of the pathophysiology, possible treatments, and the most (not all) representative examples of the latest advancements.

Modulation of blood-brain tumor barrier for delivery of magnetic hyperthermia to brain cancer

Glioblastoma (GBM) is the most invasive brain tumor and remains lack of effective treatment. The existence of blood-brain tumor barrier (BBTB) constitutes the greatest barrier to non-invasive delivery of therapeutic agents to tumors in the brain. Here, we propose a novel approach to specifically modulate BBTB and deliver magnetic hyperthermia in a systemic delivery mode for the treatment of GBM. BBTB modulation is achieved by targeted delivering fingolimod to brain tumor region via dual redox responsive PCL-SeSe-PEG (poly (ε-caprolactone)-diselenium-poly (ethylene glycol)) polymeric nanocarrier. As an antagonist of sphingosine 1-phosphate receptor-1 (S1P₁), fingolimod potently inhibits the barrier function of BBB by blocking the binding of sphingosine 1-phosphate (S1P) to S1P1 in endothelial cells. We found that the modulated BBTB showed slight expression level of tight junction proteins, allowing efficient accumulation of zinc- and cobalt- doped iron oxide nanoclusters (ZnCoFe NCs) with enhanced magnetothermal conversion efficiency into tumor tissues through the paracellular pathway. As a result, the co-delivery of heat shock protein 70 inhibitor VER-155008 with ZnCoFe NCs could realize synergistic magnetic hyperthermia effects upon exposure to an alternating current magnetic field (ACMF) in both GL261 and U87 brain tumor models. This modulation approach brings new ideas for the treatment of central nervous system diseases that require delivery of therapeutic agents across the blood-brain barrier (BBB).

Application of nanomaterials in diagnosis and treatment of glioblastoma

Diagnosing and treating glioblastoma patients is currently hindered by several obstacles, such as tumor heterogeneity, the blood-brain barrier, tumor complexity, drug efflux pumps, and tumor immune escape mechanisms. Combining multiple methods can increase benefits against these challenges. For example, nanomaterials can improve the curative effect of glioblastoma treatments, and the synergistic combination of different drugs can markedly reduce their side effects. In this review, we discuss the progression and main issues regarding glioblastoma diagnosis and treatment, the classification of nanomaterials, and the delivery mechanisms of nanomedicines. We also examine tumor targeting and promising nano-diagnosis or treatment principles based on nanomedicine. We also summarize the progress made on the advanced application of combined nanomaterial-based diagnosis and treatment tools and discuss their clinical prospects. This review aims to provide a better understanding of nano-drug combinations, nano-diagnosis, and treatment options for glioblastoma, as well as insights for developing new tools.

Transmigration of magnetite nanoparticles across the blood-brain barrier in a rodent model: influence of external and alternating magnetic fields

Despite advances in neurology, drug delivery to the central nervous system is considered a challenge due to the presence of the blood brain barrier (BBB). In this study, the role of magnetic hyperthermia induced by exposure of magnetic nanoparticles (MNPs) to an alternating magnetic field (AMF) in synergy with an external magnetic field (EMF) was investigated to transiently increase the permeability of the MNPs across the BBB. A dual magnetic targeting approach was employed by first dragging the MNPs by an EMF for an intended enhanced cellular association with the brain endothelial cells and then activating the MNPs by an AMF for the temporary disruption of the tight junctions of BBB. The efficacy of the BBB permeability for the MNPs under the influence of dual magnetic targeting was evaluated in vitro using transwell models developed by co-culturing murine brain endothelial cells with astrocytes, as well as in vivo in mouse models. The in vitro results revealed that the exposure to AMF transiently opened the tight junctions at the BBB, which, after 3 h of treatment, were observed to recover back to their comparable control levels. A biodistribution analysis of nanoparticles confirmed targeted accumulation of MNPs in the brain following dual targeting. This dual targeting approach was observed to open the tight junctions, thus increasing the transport of MNPs into the brain with higher specificity as compared to using EMF targeting alone, suggesting that a dual magnetic targeting-induced transport of MNPs across the BBB is an effective measure for delivery of therapeutics.

Angiopep-2-decorated titanium-alloy core-shell magnetic nanoparticles for nanotheranostics and medical imaging

The poor permeability of therapeutic agents across the blood-brain barrier and blood-tumor barrier is a significant barrier in glioma treatment. Low-density lipoprotein receptor-related protein (LRP-1) recognises a dual-targeting ligand, angiopep-2, which is overexpressed in the BBB and gliomas. Here, we have synthesized Ti@FeAu core-shell nanoparticles conjugated with angiopep-2 (Ti@FeAu-Ang nanoparticles) to target glioma cells and treat brain cancer via hyperthermia produced by a magnetic field. Our results confirmed that Ti@FeAu core-shell nanoparticles were superparamagnetic, improved the negative contrast effect on glioma, and exhibited a temperature elevation of 12° C upon magnetic stimulation, which implies potential applications in magnetic resonance imaging (MRI) and hyperthermia-based cancer therapy. Angiopep-2-decorated nanoparticles exhibited higher cellular uptake by C6 glioma cells than by L929 fibroblasts, demonstrating selective glioma targeting and improved cytotoxicity up to 85% owing to hyperthermia produced by a magnetic field. The in vivo findings demonstrated that intravenous injection of Ti@FeAu-Ang nanoparticles exhibited a 10-fold decrement in tumor volume compared to the control group. Furthermore, immunohistochemical analysis of Ti@FeAu-Ang nanoparticles showed that coagulative necrosis of tumor tissues and preliminary safety analysis highlighted no toxicity to the haematological system, after Ti@FeAu-Ang nanoparticle-induced hyperthermia treatment.

Engineering Gold Shelled Nanomagnets for Pre-Setting the Operating Temperature for Magnetic Hyperthermia

This study investigated the fabrication of spherical gold shelled maghemite nanoparticles for use in magnetic hyperthermia (MHT) assays. A maghemite core (14 ± 3 nm) was used to fabricate two samples with different gold thicknesses, which presented gold (g)/maghemite (m) content ratios of 0.0376 and 0.0752. The samples were tested in MHT assays (temperature versus time) with varying frequencies (100-650 kHz) and field amplitudes (9-25 mT). The asymptotic temperatures (T∞) of the aqueous suspensions (40 mg Fe/mL) were found to be in the range of 59-77 °C (naked maghemite), 44-58 °C (g/m=0.0376) and 33-51 °C (g/m=0.0752). The MHT data revealed that T∞ could be successful controlled using the gold thickness and cover the range for cell apoptosis, thereby providing a new strategy for the safe use of MHT in practice. The highest SAR (specific absorption rate) value was achieved (75 kW/kg) using the thinner gold shell layer (334 kHz, 17 mT) and was roughly twenty times bigger than the best SAR value that has been reported for similar structures. Moreover, the time that was required to achieve T∞ could be modeled by changing the thermal conductivity of the shell layer and/or the shape/size of the structure. The MHT assays were pioneeringly modeled using a derived equation that was analytically identical to the Box-Lucas method (which was reported as phenomenological).

Tailoring nanoparticles design for enhanced heating efficiency and improved magneto-chemo therapy for glioblastoma

Development of multifunctional magnetic nanomaterials (MNPs) with improved heat-generating capabilities and effective combination with localized chemotherapy has emerged as a promising therapeutic regime for solid tumors like glioblastoma. In this regard, the shape-dependent hyperthermic and chemo-therapeutic potential of nanomaterials, has not been extensively explored. Here we present, development of various morphological designs of MNPs including spherical, clusters, rods and cubic; to compare the effect of shape on tuning the properties of MNPs that are relevant to many potential biomedical applications like drug delivery, cellular uptake and heat generation. The study includes extensive comparison of morpho-structural characteristics, size distributions, chemical composition, surface area measurements and magnetic properties of the variable shaped MNPs. Further the heating efficiencies in aqueous and cellular environments and heat triggered drug release profiles for successful magneto-chemotherapy were compared among all in-house synthesized MNPs. Under biosafety limit considerations given by Hergt's limit (H*f value <5 × 10⁹ Am^-1 s^-1), cuboidal shaped MNPs demonstrated highest heating efficiency owing to magnetosome-like chain formation along with sustained drug release profile as compared to other synthesized MNPs. The mechanism of cancer cell death mediated via magneto-chemotherapy was elucidated to be the oxidative stress-mediated apoptotic cell death pathway. In vivo studies further demonstrated complete tumor regression only in the magneto-chemotherapy treated group. These findings suggest the potential of combinatorial therapy to overcome the clinical limitations of the independent therapies for advanced thermotherapy of glioblastoma.

Sensitization of glioblastoma cancer cells to radiotherapy and magnetic hyperthermia by targeted temozolomide-loaded magnetite tri-block copolymer nanoparticles as a nanotheranostic agent

AIMS

Recently, the development of new strategies in the treatment and diagnosis of cancer cells such as thermo-radiation-sensitizer and theranostic agents have received a great deal of attention. In this work, folic acid-conjugated temozolomide-loaded SPION@PEG-PBA-PEG nanoparticles (TMZ-MNP-FA NPs) were proposed for use as magnetic resonance imaging (MRI) contrast agents and to enhance the cytotoxic effects of hyperthermia and radiotherapy.

MAIN METHODS

Nanoparticles were synthesized by the Nano-precipitation method and their characteristics were determined by dynamic light scattering (DLS), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). To evaluate the thermo-radio-sensitization effects of NPs, C6 cells were treated with nanoparticles for 24 h and then exposed to 6-MV X-ray radiation. After radiotherapy, the cells were subjected to an alternating magnetic field (AMF) hyperthermia. The therapeutic potential was assessed using clonogenic assay, ROS generation measurement, flow cytometry assay, and qRT-PCR analysis. Also, the diagnostic properties of the nanoparticles were assessed by MRI.

KEY FINDINGS

MRI scanning indicated that nanoparticles accumulated in C6 cells could be tracked by T2-weighted MR imaging. Colony formation assay proved that TMZ-MNP-FA NPs enhanced the anti-proliferation effects of AMF by 1.94-fold compared to AMF alone (P < 0.0001). Moreover, these NPs improved the radiation effects with a dose enhancement factor of 1.65. All results showed that the combination of carrier-based chemotherapy with hyperthermia and radiotherapy caused a higher anticancer efficacy than single- or two-modality treatments.

SIGNIFICANCE

The nanoparticles advanced in this study can be proposed as the promising theranostic and thermo-radio-sensitizer platform for the diagnosis and tri-modal synergistic cancer therapy.

Enhanced postoperative cancer therapy by iron-based hydrogels

Surgical resection is a widely used method for the treatment of solid tumor cancers. However, the inhibition of tumor recurrence and metastasis are the main challenges of postoperative tumor therapy. Traditional intravenous or oral administration have poor chemotherapeutics bioavailability and undesirable systemic toxicity. Polymeric hydrogels with a three-dimensional network structure enable on-site delivery and controlled release of therapeutic drugs with reduced systemic toxicity and have been widely developed for postoperative adjuvant tumor therapy. Among them, because of the simple synthesis, good biocompatibility, biodegradability, injectability, and multifunctionality, iron-based hydrogels have received extensive attention. This review has summarized the general synthesis methods and construction principles of iron-based hydrogels, highlighted the latest progress of iron-based hydrogels in postoperative tumor therapy, including chemotherapy, photothermal therapy, photodynamic therapy, chemo-dynamic therapy, and magnetothermal-chemical combined therapy, etc. In addition, the challenges towards clinical application of iron-based hydrogels have also been discussed. This review is expected to show researchers broad perspectives of novel postoperative tumor therapy strategy and provide new ideas in the design and application of novel iron-based hydrogels to advance this sub field in cancer nanomedicine.

Superparamagnetic Hyperthermia Study with Cobalt Ferrite Nanoparticles Covered with γ-Cyclodextrins by Computer Simulation for Application in Alternative Cancer Therapy

In this paper, we present a study by computer simulation on superparamagnetic hyperthermia with CoFe2O4 ferrimagnetic nanoparticles coated with biocompatible gamma-cyclodextrins (γ-CDs) to be used in alternative cancer therapy with increased efficacy and non-toxicity. The specific loss power that leads to the heating of nanoparticles in superparamagnetic hyperthermia using CoFe2O4-γ-CDs was analyzed in detail depending on the size of the nanoparticles, the thickness of the γ-CDs layer on the nanoparticle surface, the amplitude and frequency of the alternating magnetic field, and the packing fraction of nanoparticles, in order to find the proper conditions in which the specific loss power is maximal. We found that the maximum specific loss power was determined by the Brown magnetic relaxation processes, and the maximum power obtained was significantly higher than that which would be obtained by the Néel relaxation processes under the same conditions. Moreover, increasing the amplitude of the magnetic field led to a significant decrease in the optimal diameter at which the maximum specific loss power is obtained (e.g., for 500 kHz frequency the optimal diameter decreased from 13.6 nm to 9.8 nm when the field increased from 10 kA/m to 50 kA/m), constituting a major advantage in magnetic hyperthermia for its optimization, in contrast to the known results in the absence of cyclodextrins from the surface of immobilized nanoparticles of CoFe2O4, where the optimal diameter remained practically unchanged at ~6.2 nm.

Recent advances in the therapeutic strategies of glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the most common, most formidable, and deadliest malignant types of primary astrocytoma with a poor prognosis. At present, the standard of care includes surgical tumor resection, followed by radiation therapy concomitant with chemotherapy and temozolomide. New developments and significant advances in the treatment of GBM have been achieved in recent decades. However, despite the advances, recurrence is often inevitable, and the survival of patients remains low. Various factors contribute to the difficulty in identifying an effective therapeutic option, among which are tumor complexity, the presence of the blood-brain barrier (BBB), and the presence of GBM cancer stem cells, prompting the need for improving existing treatment approaches and investigating new treatment alternatives for ameliorating the treatment strategies of GBM. In this review, we outline some of the most recent literature on the various available treatment options such as surgery, radiotherapy, cytotoxic chemotherapy, gene therapy, immunotherapy, phototherapy, nanotherapy, and tumor treating fields in the treatment of GBM, and we list some of the potential future directions of GBM. The reviewed studies confirm that GBM is a sophisticated disease with several challenges for scientists to address. Hence, more studies and a multimodal therapeutic approach are crucial to yield an effective cure and prolong the survival of GBM patients.

Synthesis and Characterization of Magnetic Composite Theragnostics by Nano Spray Drying

Composites of magnetite nanoparticles encapsulated with polymers attract interest for many applications, especially as theragnostic agents for magnetic hyperthermia, drug delivery, and magnetic resonance imaging. In this work, magnetite nanoparticles were synthesized by coprecipitation and encapsulated with different polymers (Eudragit S100, Pluronic F68, Maltodextrin, and surfactants) by nano spray drying technique, which can produce powders of nanoparticles from solutions or suspensions. Transmission and scanning electron microscopy images showed that the bare magnetite nanoparticles have 10.5 nm, and after encapsulation, the particles have approximately 1 μm, with size and shape depending on the material’s composition. The values of magnetic saturation by SQUID magnetometry and mass residues by thermogravimetric analysis were used to characterize the magnetic content in the materials, related to their magnetite/polymer ratios. Zero-field-cooling and field-cooling (ZFC/FC) measurements showed how blocking temperatures of the powders of the composites are lower than that of bare magnetite, possibly due to lower magnetic coupling, being an interesting system to study magnetic interactions of nanoparticles. Furthermore, studies of cytotoxic effect, hydrodynamic size, and heating capacity for hyperthermia (according to the application of an alternate magnetic field) show that these composites could be applied as a theragnostic material for a non-invasive administration such as nasal.

Progress and Viewpoints of Multifunctional Composite Nanomaterials for Glioblastoma Theranostics

The most common malignant tumor of the brain is glioblastoma multiforme (GBM) in adults. Many patients die shortly after diagnosis, and only 6% of patients survive more than 5 years. Moreover, the current average survival of malignant brain tumors is only about 15 months, and the recurrence rate within 2 years is almost 100%. Brain diseases are complicated to treat. The reason for this is that drugs are challenging to deliver to the brain because there is a blood–brain barrier (BBB) protection mechanism in the brain, which only allows water, oxygen, and blood sugar to enter the brain through blood vessels. Other chemicals cannot enter the brain due to their large size or are considered harmful substances. As a result, the efficacy of drugs for treating brain diseases is only about 30%, which cannot satisfy treatment expectations. Therefore, researchers have designed many types of nanoparticles and nanocomposites to fight against the most common malignant tumors in the brain, and they have been successful in animal experiments. This review will discuss the application of various nanocomposites in diagnosing and treating GBM. The topics include (1) the efficient and long-term tracking of brain images (magnetic resonance imaging, MRI, and near-infrared light (NIR)); (2) breaking through BBB for drug delivery; and (3) natural and chemical drugs equipped with nanomaterials. These multifunctional nanoparticles can overcome current difficulties and achieve progressive GBM treatment and diagnosis results.

Small-angle X-ray scattering to quantify the incorporation and analyze the disposition of magnetic nanoparticles inside cells

Access to detailed information on cells loaded with nanoparticles with nanoscale precision is of a long-standing interest in many areas of nanomedicine. In this context, designing a single experiment able to provide statistical mean data from a large number of living unsectioned cells concerning information on the nanoparticle size and aggregation inside cell endosomes and accurate nanoparticle cell up-take is of paramount importance. Small-angle X-ray scattering (SAXS) is presented here as a tool to achieve such relevant data. Experiments were carried out in cultures of B16F0 murine melanoma and A549 human lung adenocarcinoma cell lines loaded with various iron oxide nanostructures displaying distinctive structural characteristics. Five systems of water-dispersible magnetic nanoparticles (MNP) of different size, polydispersity and morphology were analyzed, namely, nearly monodisperse MNP with 11 and 13 nm mean size coated with meso-2,3-dimercaptosuccinic acid, more polydisperse 6 nm colloids coated with citric acid and two nanoflowers (NF) systems of 24 and 27 nm in size resulting from the aggregation of 8 nm MNP. Up-take was determined for each system using B16F0 cells. Here we show that SAXS pattern provides high resolution information on nanoparticles disposition inside endosomes of the cytoplasm through the structure factor analysis, on nanoparticles size and dispersity after their incorporation by the cell and on up-take quantification from the extrapolation of the intensity in absolute scale to null scattering vector. We also report on the cell culture preparation to reach sensitivity for the observation of MNP inside cell endosomes using high brightness SAXS synchrotron source. Our results show that SAXS can become a valuable tool for analyzing MNP in cells and tissues.

Oral Cancer Theranostic Application of FeAu Bimetallic Nanoparticles Conjugated with MMP-1 Antibody

Metastatic oral squamous cell carcinoma (SCC) displays a poor disease prognosis with a 5-year survival rate of 39%. Chemotherapy has emerged as the mainstream treatment against small clusters of cancer cells but poses more risks than benefits for metastatic cells due to the non-specificity and cytotoxicity. To overcome these obstacles, we conjugated antibodies specific for matrix metalloproteinase-1 (MMP-1), a prognostic biomarker of SCC, to iron–gold bimetallic nanoparticles (FeAu NPs) and explored the capability of this complex to target and limit SSC cell growth via magnetic field-induced hyperthermia. Our results showed that 4.32 ± 0.79 nm sized FeAu NPs were superparamagnetic in nature with a saturation magnetization (Ms) of 5.8 emu/g and elevated the media temperature to 45 °C, confirming the prospect to deliver hyperthermia. Furthermore, conjugation with MMP-1 antibodies resulted in a 3.07-fold higher uptake in HSC-3 (human tongue squamous cell carcinoma) cells as compared to L929 (fibroblast) cells, which translated to a 5-fold decrease in cell viability, confirming SCC targeting. Finally, upon magnetic stimulation, MMP-1-FeAu NPs conjugate triggered 89% HSC-3 cellular death, confirming the efficacy of antibody-conjugated nanoparticles in limiting SCC growth. The synergistic effect of biomarker-specific antibodies and magnetic nanoparticle-induced hyperthermia may open new doors towards SCC targeting for improved disease prognosis.

Iron Oxide Nanoparticles: Physicochemical Characteristics and Historical Developments to Commercialization for Potential Technological Applications

Iron oxide nanoparticles (IONPs) have gained increasing attention in various biomedical and industrial sectors due to their physicochemical and magnetic properties. In the biomedical field, IONPs are being developed for enzyme/protein immobilization, magnetofection, cell labeling, DNA detection, and tissue engineering. However, in some established areas, such as magnetic resonance imaging (MRI), magnetic drug targeting (MDT), magnetic fluid hyperthermia (MFH), immunomagnetic separation (IMS), and magnetic particle imaging (MPI), IONPs have crossed from the research bench, received clinical approval, and have been commercialized. Additionally, in industrial sectors IONP-based fluids (ferrofluids) have been marketed in electronic and mechanical devices for some time. This review explores the historical evolution of IONPs to their current state in biomedical and industrial applications.

Glioblastoma multiforme (GBM): An overview of current therapies and mechanisms of resistance

Glioblastoma multiforme (GBM) is a WHO grade IV glioma and the most common malignant, primary brain tumor with a 5-year survival of 7.2%. Its highly infiltrative nature, genetic heterogeneity, and protection by the blood brain barrier (BBB) have posed great treatment challenges. The standard treatment for GBMs is surgical resection followed by chemoradiotherapy. The robust DNA repair and self-renewing capabilities of glioblastoma cells and glioma initiating cells (GICs), respectively, promote resistance against all current treatment modalities. Thus, durable GBM management will require the invention of innovative treatment strategies. In this review, we will describe biological and molecular targets for GBM therapy, the current status of pharmacologic therapy, prominent mechanisms of resistance, and new treatment approaches. To date, medical imaging is primarily used to determine the location, size and macroscopic morphology of GBM before, during, and after therapy. In the future, molecular and cellular imaging approaches will more dynamically monitor the expression of molecular targets and/or immune responses in the tumor, thereby enabling more immediate adaptation of tumor-tailored, targeted therapies.

In Vitro Evaluation of Hyperthermia Magnetic Technique Indicating the Best Strategy for Internalization of Magnetic Nanoparticles Applied in Glioblastoma Tumor Cells

This in vitro study aims to evaluate the magnetic hyperthermia (MHT) technique and the best strategy for internalization of magnetic nanoparticles coated with aminosilane (SPIONAmine) in glioblastoma tumor cells. SPIONAmine of 50 and 100 nm were used for specific absorption rate (SAR) analysis, performing the MHT with intensities of 50, 150, and 300 Gauss and frequencies varying between 305 and 557 kHz. The internalization strategy was performed using 100, 200, and 300 µgFe/mL of SPIONAmine, with or without Poly-L-Lysine (PLL) and filter, and with or without static or dynamic magnet field. The cell viability was evaluated after determination of MHT best condition of SPIONAmine internalization. The maximum SAR values of SPIONAmine (50 nm) and SPIONAmine (100 nm) identified were 184.41 W/g and 337.83 W/g, respectively, using a frequency of 557 kHz and intensity of 300 Gauss (≈23.93 kA/m). The best internalization strategy was 100 µgFe/mL of SPIONAmine (100 nm) using PLL with filter and dynamic magnet field, submitted to MHT for 40 min at 44 °C. This condition displayed 70.0% decreased in cell viability by flow cytometry and 68.1% by BLI. We can conclude that our study is promising as an antitumor treatment, based on intra- and extracellular MHT effects. The optimization of the nanoparticles internalization process associated with their magnetic characteristics potentiates the extracellular acute and late intracellular effect of MHT achieving greater efficiency in the therapeutic process.

Transportation of Single-Domain Antibodies through the Blood-Brain Barrier

Single-domain antibodies derive from the heavy-chain-only antibodies of Camelidae (camel, dromedary, llama, alpaca, vicuñas, and guananos; i.e., nanobodies) and cartilaginous fishes (i.e., VNARs). Their small size, antigen specificity, plasticity, and potential to recognize unique conformational epitopes represent a diagnostic and therapeutic opportunity for many central nervous system (CNS) pathologies. However, the blood–brain barrier (BBB) poses a challenge for their delivery into the brain parenchyma. Nevertheless, numerous neurological diseases and brain pathologies, including cancer, result in BBB leakiness favoring single-domain antibodies uptake into the CNS. Some single-domain antibodies have been reported to naturally cross the BBB. In addition, different strategies and methods to deliver both nanobodies and VNARs into the brain parenchyma can be exploited when the BBB is intact. These include device-based and physicochemical disruption of the BBB, receptor and adsorptive-mediated transcytosis, somatic gene transfer, and the use of carriers/shuttles such as cell-penetrating peptides, liposomes, extracellular vesicles, and nanoparticles. Approaches based on single-domain antibodies are reaching the clinic for other diseases. Several tailoring methods can be followed to favor the transport of nanobodies and VNARs to the CNS, avoiding the limitations imposed by the BBB to fulfill their therapeutic, diagnostic, and theragnostic promises for the benefit of patients suffering from CNS pathologies.

Magnetic Particle Imaging: Current and Future Applications, Magnetic Nanoparticle Synthesis Methods and Safety Measures

Magnetic nanoparticles (MNPs) have a wide range of applications; an area of particular interest is magnetic particle imaging (MPI). MPI is an imaging modality that utilizes superparamagnetic iron oxide particles (SPIONs) as tracer particles to produce highly sensitive and specific images in a broad range of applications, including cardiovascular, neuroimaging, tumor imaging, magnetic hyperthermia and cellular tracking. While there are hurdles to overcome, including accessibility of products, and an understanding of safety and toxicity profiles, MPI has the potential to revolutionize research and clinical biomedical imaging. This review will explore a brief history of MPI, MNP synthesis methods, current and future applications, and safety concerns associated with this newly emerging imaging modality.

Therapeutic response differences between 2D and 3D tumor models of magnetic hyperthermia

Magnetic hyperthermia-based cancer therapy (MHCT) has surfaced as one of the promising techniques for inaccessible solid tumors. It involves generation of localized heat in the tumor tissues on application of an alternating magnetic field in the presence of magnetic nanoparticles (MNPs). Unfortunately, lack of precise temperature and adequate MNP distribution at the tumor site under in vivo conditions has limited its application in the biomedical field. Evaluation of in vitro tumor models is an alternative for in vivo models. However, generally used in vitro two-dimensional (2D) models cannot mimic all the characteristics of a patient's tumor and hence, fail to establish or address the experimental variables and concerns. Considering that three-dimensional (3D) models have emerged as the best possible state to replicate the in vivo conditions successfully in the laboratory for most cell types, it is possible to conduct MHCT studies with higher clinical relevance for the analysis of the selection of magnetic parameters, MNP distribution, heat dissipation, action and acquired thermotolerance in cancer cells. In this review, various forms of 3D cultures have been considered and the successful implication of MHCT on them has been summarized, which includes tumor spheroids, and cultures grown in scaffolds, cell culture inserts and microfluidic devices. This review aims to summarize the contrast between 2D and 3D in vitro tumor models for pre-clinical MHCT studies. Furthermore, we have collated and discussed the usefulness, suitability, pros and cons of these tumor models. Even though numerous cell culture models have been established, further investigations on the new pre-clinical models and selection of best fit model for successful MHCT applications are still necessary to confer a better understanding for researchers.

Theoretical Study on Specific Loss Power and Heating Temperature in CoFe2O4 Nanoparticles as Possible Candidate for Alternative Cancer Therapy by Superparamagnetic Hyperthemia

In this paper, we present a theoretical study on the maximum specific loss power in the admissible biological limit (PsM)l for CoFe2O4 ferrimagnetic nanoparticles, as a possible candidate in alternative and non-invasive cancer therapy by superparamagnetic hyperthermia. The heating time of the nanoparticles (Δto) at the optimum temperature of approx. 43 °C for the efficient destruction of tumor cells in a short period of time, was also studied. We found the maximum specific loss power PsM (as a result of superparamegnetic relaxation in CoFe2O4 nanoparticles) for very small diameters of the nanoparticles (Do), situated in the range of 5.88–6.67 nm, and with the limit frequencies (fl) in the very wide range of values of 83–1000 kHz, respectively. Additionally, the optimal heating temperature (To) of 43 °C was obtained for a very wide range of values of the magnetic field H, of 5–60 kA/m, and the corresponding optimal heating times (Δto) were found in very short time intervals in the range of ~0.3–44 s, depending on the volume packing fraction (ε) of the nanoparticles. The obtained results, as well as the very wide range of values for the amplitude H and the frequency f of the external alternating magnetic field for which superparamagnetic hyperthermia can be obtained, which are great practical benefits in the case of hyperthermia, demonstrate that CoFe2O4 nanoparticles can be successfully used in the therapy of cancer by superaparamagnetic hyperthermia. In addition, the very small size of magnetic nanoparticles (only a few nm) will lead to two major benefits in cancer therapy via superparamagnetic hyperthermia, namely: (i) the possibility of intracellular therapy which is much more effective due to the ability to destroy tumor cells from within and (ii) the reduced cell toxicity.

Exosome-based hybrid nanostructures for enhanced tumor targeting and hyperthermia therapy

Recently, natural exosomes have attracted attention as an ideal drug carrier to overcome the limitations of existing drug delivery systems which are toxicity induction and low cancer-targeting performance. In this study, we propose an exosome-based hybrid nanostructure (EHN) with improved targeting ability and therapeutic efficacy against colorectal cancer by using exosomes isolated from the tumor cell line as a drug carrier. The proposed EHN can have high biocompatibility by using exosomes, a biologically derived material, and show improved targeting performance by adding a tumor-targeting ligand (folic acid). In addition, the proposed EHN is capable of chemotherapy because doxorubicin, an anticancer drug, is encapsulated by the exosome with high efficiency, and it can induce hyperthermia therapy because of the magnetic nanoparticles (MNPs) attached to the surface of exosomes. Through in vitro and in vivo experiments using a xenograft tumor mouse model, it was confirmed that the proposed EHN could exhibit increased apoptosis and excellent tumor growth inhibition ability. Therefore, the proposed EHN is expected to overcome the limitations of existing drug delivery systems and be utilized as an effective drug delivery system in cancer treatment.

(Carboxymethyl-stevioside)-coated magnetic dots for enhanced magnetic hyperthermia and improved glioblastoma treatment

The use of different types of biomaterials as surfactant moities has a defined role in magnetic hyperthermia-mediated cancer therapy (MHCT). In this work, we present carboxymethyl-stevioside (CMS)-modified magnetic dots (MDs) as efficient magnetic hyperthermia agents for glioma therapy. The synthesized MDs with CMS biosurfactant coating exhibited significant water stability that resulted in a remarkable specific absorption rate of 209.25 W/g on application of alternating magnetic field of strength 359 kHz and 188 Oe. The MDs further demonstrated significant anti-migratory and anti-invasive effect on glioma C6 cells by inhibiting the gene expression of matrix metalloproteinases-2 and -9. The effect of immediate and long term hyperthermia treatment was then evaluated after repetitive exposure to hyperthermia, in terms of glioma cell viability, the effect of treatment on cell morphology, the cell cycle distribution and oxidative stress generation. The results obtained suggest the promising potential of CMS-modified nano-heaters for excellent magnetic hyperthermia-mediated glioma therapy.

Effect of manganese doping on the hyperthermic profile of ferrite nanoparticles using response surface methodology

Magnetic hyperthermia-based cancer therapy mediated by magnetic nanomaterials is a promising antitumoral nanotherapy, owning to its power to generate heat under the application of an alternating magnetic field. However, although the ultimate targets of these treatments, the heating potential and its relation with the magnetic behavior of the employed magnetic nanomaterials are rarely studied. Here we provide a bridge between the heating potential and magnetic properties such as anisotropy energy constant and saturation magnetization of the nano-magnets by simultaneous investigation of both hyperthermia and magnetism under a controlled set of variables given by response surface methodology. In the study, we have simultaneously investigated the effect of various synthesis parameters like cation ratio, reaction temperature and time on the magnetic response and heat generation of manganese-doped ferrite nanomaterials synthesized by a simple hydrothermal route. The optimum generation of heat and magnetization is obtained at a cationic ratio of approximately 42 at a temperature of 100 °C for a time period of 4 h. The optimized nanomaterial was then evaluated for in vitro magnetic hyperthermia application for cancer therapy against glioblastoma in terms of cell viability, effect on cellular cytoskeleton and morphological alterations. Furthermore, the correlation between the magnetic properties of the synthesized nanomaterial with its hyperthermia output was also established using K.V.M s variable where K, V and M s are the anisotropy energy constant, volume, and saturation magnetization of the nanomaterial respectively. It was found that the intensity of heat generation decreases with an increase in K.V.M s value, beyond 950 J emu g-1.

Patient-Specific Planning for Thermal Magnetic Resonance of Glioblastoma Multiforme

Simple Summary

Hyperthermia was proven to enhance the efficacy of chemo- and radiation therapy treatment of glioblastoma multiforme, an aggressive brain tumor of poor prognosis. Despite good clinical results in other tumor types and locations, hyperthermia induced by electromagnetic waves in the radiofrequency range is not available so far for the treatment of brain tumors due to the highly sensitive surrounding tissue and lack of non-invasive therapy monitoring. ThermalMR integrates non-invasive diagnosis, therapy, and therapy monitoring in a single RF applicator device by employing radiowaves for magnetic resonance imaging, radiofrequency heating, as well as magnetic resonance thermometry. This work examines three optimization algorithms for hyperthermia treatment planning and up to ten RF applicator configurations for a cohort of nine patient models with glioblastoma multiforme. Clinical diversity is represented in target size and location and the inclusion of post-operative models. Our findings indicate the need and potential for patient-specific treatment planning and RF applicator design when targeting brain tumors.

Abstract

Thermal intervention is a potent sensitizer of cells to chemo- and radiotherapy in cancer treatment. Glioblastoma multiforme (GBM) is a potential clinical target, given the cancer’s aggressive nature and resistance to current treatment options. This drives research into optimization algorithms for treatment planning as well as radiofrequency (RF) applicator design for treatment delivery. In this work, nine clinically realistic GBM target volumes (TVs) for thermal intervention are compared using three optimization algorithms and up to ten RF applicator designs for thermal magnetic resonance. Hyperthermia treatment planning (HTP) was successfully performed for all cases, including very small, large, and even split target volumes. Minimum requirements formulated for the metrics assessing HTP outcome were met and exceeded for all patient specific cases. Results indicate a 16 channel two row arrangement to be most promising. HTP of TVs with a small extent in the cranial–caudal direction in conjunction with a large radial extent remains challenging despite the advanced optimization algorithms used. In general, deep seated targets are favorable. Overall, our findings indicate that a one-size-fits-all RF applicator might not be the ultimate approach in hyperthermia of brain tumors. It stands to reason that modular and reconfigurable RF applicator configurations might best suit the needs of targeting individual GBM geometry.

Mitigation of magnetic particle hyperthermia side effects by magnetic field controls

Objective: In magnetic particle hyperthermia, a promising least-invasive cancer treatment, malignant regions in proximity with magnetic nanoparticles undergo heat stress, while unavoidably surrounding healthy tissues may also suffer from heat either directly or indirectly by the induced eddy currents, due to the developed electric fields as well. Here, we propose a facile upgrade of a typical magnetic particle hyperthermia protocol, to selectively mitigate eddy currents' heating without compromising the beneficial role of heating in malignant regions.Method: The key idea is to apply the external magnetic field intermittently (in an ON/OFF pulse mode), instead of the continuous field mode typically applied. The parameters of the intermittent field mode, such as time intervals (ON time: 25-100 s, OFF time: 50-200 s, Duty Cycle:16-100%) and field amplitude (30-70 mT) are optimized based on evaluation on healthy tissue and cancer tissue phantoms. The goal is to sustain in cancer tissue phantom the maximum temperature increase (preferably within 4-8°C above body temperature of 37°C), while in the healthy tissue phantom temperature variation is suppressed far below the 4°C dictating the eddy current mitigation.Results: Optimum conditions of intermittent field (ON/OFF: 50/100 in s, Duty Cycle: 33%, magnetic field: 45mT) are then examined in ex-vivo samples verifying the successful suppression of eddy currents. Simultaneously, a well-elaborated theoretical approach provides a rapid calculation of temperature increase and, furthermore, the ability to quickly simulate a variety of duty cycle times and field controls may save experimental time.Conclusion: Eventually, the application of an intermittent field mode in a magnetic particle hyperthermia protocol, succeeds in eddy current mitigation in surrounding tissues and allows for the application of larger field amplitudes that may augment hyperthermia efficiency without objecting typical biomedical applicability field constraints such as Brezovich criterion.

Perspective of mesenchymal transformation in glioblastoma

Despite aggressive multimodal treatment, glioblastoma (GBM), a grade IV primary brain tumor, still portends a poor prognosis with a median overall survival of 12–16 months. The complexity of GBM treatment mainly lies in the inter- and intra-tumoral heterogeneity, which largely contributes to the treatment-refractory and recurrent nature of GBM. By paving the road towards the development of personalized medicine for GBM patients, the cancer genome atlas classification scheme of GBM into distinct transcriptional subtypes has been considered an invaluable approach to overcoming this heterogeneity. Among the identified transcriptional subtypes, the mesenchymal subtype has been found associated with more aggressive, invasive, angiogenic, hypoxic, necrotic, inflammatory, and multitherapy-resistant features than other transcriptional subtypes. Accordingly, mesenchymal GBM patients were found to exhibit worse prognosis than other subtypes when patients with high transcriptional heterogeneity were excluded. Furthermore, identification of the master mesenchymal regulators and their downstream signaling pathways has not only increased our understanding of the complex regulatory transcriptional networks of mesenchymal GBM, but also has generated a list of potent inhibitors for clinical trials. Importantly, the mesenchymal transition of GBM has been found to be tightly associated with treatment-induced phenotypic changes in recurrence. Together, these findings indicate that elucidating the governing and plastic transcriptomic natures of mesenchymal GBM is critical in order to develop novel and selective therapeutic strategies that can improve both patient care and clinical outcomes. Thus, the focus of our review will be on the recent advances in the understanding of the transcriptome of mesenchymal GBM and discuss microenvironmental, metabolic, and treatment-related factors as critical components through which the mesenchymal signature may be acquired. We also take into consideration the transcriptomic plasticity of GBM to discuss the future perspectives in employing selective therapeutic strategies against mesenchymal GBM.

Nanotechnology and Nanocarrier-Based Drug Delivery as the Potential Therapeutic Strategy for Glioblastoma Multiforme: An Update

Simple Summary

Glioblastoma multiforme (GBM) are among the most lethal tumors. The highly invasive nature and presence of GBM stem cells, as well as the blood brain barrier (BBB) which limits chemotherapeutic drugs from entering the tumor mass, account for the high chance of treatment failure. Recent developments have found that nanoparticles can be conjugated to liposomes, dendrimers, metal irons, or polymeric micelles, which enhance the drug-loaded compounds to efficiently penetrate the BBB, thus offering new possibilities for overcoming GBM stem cell-mediated resistance to chemotherapy and radiation therapy. In addition, there have been new emerging strategies that use nanocarriers for successful GBM treatment in animal models. This review highlights the recent development of nanotechnology and nanocarrier-based drug delivery for treatment of GBMs, which may be a promising therapeutic strategy for this tumor entity.

Abstract

Glioblastoma multiforme (GBM) is the most common and malignant brain tumor with poor prognosis. The heterogeneous and aggressive nature of GBMs increases the difficulty of current standard treatment. The presence of GBM stem cells and the blood brain barrier (BBB) further contribute to the most important compromise of chemotherapy and radiation therapy. Current suggestions to optimize GBM patients’ outcomes favor controlled targeted delivery of chemotherapeutic agents to GBM cells through the BBB using nanoparticles and monoclonal antibodies. Nanotechnology and nanocarrier-based drug delivery have recently gained attention due to the characteristics of biosafety, sustained drug release, increased solubility, and enhanced drug bioactivity and BBB penetrability. In this review, we focused on recently developed nanoparticles and emerging strategies using nanocarriers for the treatment of GBMs. Current studies using nanoparticles or nanocarrier-based drug delivery system for treatment of GBMs in clinical trials, as well as the advantages and limitations, were also reviewed.

Optimization Study on Specific Loss Power in Superparamagnetic Hyperthermia with Magnetite Nanoparticles for High Efficiency in Alternative Cancer Therapy

The cancer therapy with the lowest possible toxicity is today an issue that raises major difficulties in treating malignant tumors because chemo- and radiotherapy currently used in this field have a high degree of toxicity and in many cases are ineffective. Therefore, alternative solutions are rapidly being sought in cancer therapy, in order to increase efficacy and a reduce or even eliminate toxicity to the body. One of the alternative methods that researchers believe may be the method of the future in cancer therapy is superparamagnetic hyperthermia (SPMHT), because it can be effective in completely destroying tumors while maintaining low toxicity or even without toxicity on the healthy tissues. Superparamagnetic hyperthermia uses the natural thermal effect in the destruction of cancer cells, obtained as a result of the phenomenon of superparamagnetic relaxation of the magnetic nanoparticles (SPMNPs) introduced into the tumor; SPMNPs can heat the cancer cells to 42-43 °C under the action of an external alternating magnetic field with frequency in the range of hundreds of kHz. However, the effectiveness of this alternative method depends very much on finding the optimal conditions in which this method must be applied during the treatment of cancer. In addition to the type of magnetic nanoparticles and the biocompatibility with the biological tissue or nanoparticles biofunctionalization that must be appropriate for the intended purpose a key parameter is the size of the nanoparticles. Also, establishing the appropriate parameters for the external alternating magnetic field (AMF), respectively the amplitude and frequency of the magnetic field are very important in the efficiency and effectiveness of the magnetic hyperthermia method. This paper presents a 3D computational study on specific loss power (Ps) and heating temperature (ΔT) which allows establishing the optimal conditions that lead to efficient heating of Fe₃O₄ nanoparticles, which were found to be the most suitable for use in superparamagnetic hyperthermia (SPMHT), as a non-invasive and alternative technique to chemo- and radiotherapy. The size (diameter) of the nanoparticles (D), the amplitude of the magnetic field (H) and the frequency (f) of AMF were established in order to obtain maximum efficiency in SPMHT and rapid heating of magnetic nanoparticles at the required temperature of 42-43 °C for irreversible destruction of tumors, without affecting healthy tissues. Also, an analysis on the amplitude of the AMF is presented, and how its amplitude influences the power loss and, implicitly, the heating temperature, observables necessary in SPMHT for the efficient destruction of tumor cells. Following our 3D study, we found for Fe₃O₄ nanoparticles the optimal diameter of ~16 nm, the optimal range for the amplitude of the magnetic field of 10-25 kA/m and the optimal frequency within the biologically permissible limit in the range of 200-500 kHz. Under the optimal conditions determined for the nanoparticle diameter of 16.3 nm, the magnetic field of 15 kA/m and the frequency of 334 kHz, the magnetite nanoparticles can be quickly heated to obtain the maximum hyperthermic effect on the tumor cells: in only 4.1-4.3 s the temperature reaches 42-43 °C, required in magnetic hyperthermia, with major benefits in practical application in vitro and in vivo, and later in clinical trials.

Advances in drug delivery technology for the treatment of glioblastoma multiforme

Glioblastoma multiforme (GBM) is a particularly aggressive and malignant type of brain tumor, notorious for its high recurrence rate and low survival rate. The treatment of GBM is challenging mainly because several issues associated with the GBM microenvironment have not yet been resolved. These obstacles originate from a variety of factors such as genetics, anatomy, and cytology, all of which collectively hinder the treatment of GBM. Recent advances in materials and device engineering have presented new perspectives with regard to unconventional drug administration methods for GBM treatment. Such novel drug delivery approaches, based on the clear understanding of the intrinsic properties of GBM, have shown promise in overcoming some of the obstacles. In this review, we first recapitulate the first-line therapy and clinical challenges in the current treatment of GBM. Afterwards, we introduce the latest technological advances in drug delivery strategies to improve the efficiency for GBM treatment, mainly focusing on materials and devices. We describe such efforts by classifying them into two categories, systemic and local drug delivery. Finally, we discuss unmet challenges and prospects for the clinical translation of these drug delivery technologies.